The increasing processing power of electronic devices such as computers, game consoles, personal digital assistants (PDAs) and cellular radio terminals has evoked a trend towards using more and more three-dimensional graphics. Although at the time of writing this description an almost exclusive majority of display devices are two-dimensional screens, it is possible to make them show three-dimensional graphics by utilising perspective and shadows, increasing blurredness with increasing observation distance, and using other kinds of graphical tricks that cause a human observer to perceive a two-dimensional image as if it represented truly three-dimensional objects. Three-dimensionality offers attractive possibilities of visualisation e.g. in recreational games, and makes it possible to construct completely new kinds of user interface features where the user may e.g. stroll through a three-dimensional “archive room” when looking for a particular piece of information.
A major problem related to three-dimensional graphics is the need for intuitive and easily adopted controls. The user should be able to affect the way in which he sees things in the three-dimensional “virtual world”, typically so that he “moves” therein and/or causes the objects of the virtual world to move.
The most commonly used controls of present-day electronic devices are various arrangements of pressable keys. Other kinds of known controls and input means include touch-sensitive displays, touch pads and miniature joysticks, as well as cylindrical or ball-shaped rollers. A mouse in the form used in personal computers is an aggregate of a ball-shaped roller, a number of pressable keys and nowadays also a cylindrical or wheel-shaped roller. Even steering wheels and pedals are known. Of the known control types the joystick has usually the most intuitive association with a three-dimensional virtual world, at least if a human user can use the joystick for “driving” or “flying” around in the virtually existing three-dimensional space the projection of which he sees in the two-dimensional display.
The publication U.S. Pat. No. 5,541,622 illustrates a good example of a known miniature joystick, which is also schematically shown in the exploded diagram view of FIG. 1. The visible and touchable part of the joystick arrangement is a pin 101, an elongated shaft of which goes through the central bore of an actuator plate 102. A lower surface of the actuator plate 102 comprises a number of bumps 103 distributed radially around a central vertical axis. Below the actuator plate 102 there is a thin, elastic domesheet 104 with a single contact dome centrally located below a lower end of the pin 101. The next layer is a detector sheet 105, which comprises pressure-sensitive detector elements 106 at locations that correspond to those of the bumps 103. There is also a switch pad layer 107 on top of a dielectric support layer 108. A biasing spring 109 is located between the support layer 108 and a lower base plate 110, the attachment pins of which go through the holes in all other layers to engage with respective recesses or attachment holes in the actuator plate 102.
Pushing the top end of the miniature joystick of FIG. 1 sideways causes the bumps 103 to exert varying pressing forces on the radially distributed pressure-sensitive detector elements 106. A detector circuit (not shown) coupled to receive signals from the detector elements 106 converts these signals into an indication of the direction and force with which the joystick was pushed. Pressing the top end directly downwards causes the lower end of the pin 101 to press the contact dome against a switch pad on the switch pad layer 107, which the detector circuit interpretes as a direction-independent “mouse click”.
FIG. 2 is a schematic cross sectional view of an even simpler miniature joystick structure known from the published patent application number
U.S. 2002/0070918 A1. The edges of a joystick part 201, which has an Upwards pointing shaft, are clamped under fastening means 202 that keep the joystick part 201 fastened to a dielectric circuit board 203. Directly below the joystick part 201 there are detector elements 204 on or in the dielectric circuit board 203. The lower surface of the joystick part 201 is convex by shape, so that tilting the joystick part 201 by its shaft causes different points of the convex surface to touch the detector elements. The detection mechanism can be location- and/or pressure sensitive. A detector circuit (not shown) again converts the initially obtained signal from the detector elements 204 into an indication of direction and/or force. A difference between the solutions of FIGS. 1 and 2 is that the joystick of FIG. 1 is isometric, i.e. it stays in an essentially constant position regardless of any tilting forces. The joystick of FIG. 2 can pivot back and forth by tens of degrees as a response to a tilting force. The preferred detection mechanism in said published patent application is electric contact between detector pads through a conductive layer on the convex surface, but the same principle works also with other known detection mechanisms, such as capacitive detection and pressure-dependent resistivity detection.
FIG. 3 is a schematic exploded view of a known multifunctional key, which as a control is a kind of crossbreed between a joystick and a pressable key. The visible surface of the structure consists of a circular key hat 301, below which is an elastic domesheet 302. There are a number of actuators (not shown) protruding from the lower surface of the key hat 301; here the number of actuators is assumed to be four. Below each actuator there is a contact dome in the domesheet 302. The next lower layer is a switch pad layer 303, which resembles very much the similarly named layer 107 in FIG. 1 and has a switch pad below each contact dome. There is a support layer 304 at the bottom, with possibly a biasing spring 305 attached thereto to movably support the key hat 301. Pressing different edges of the key hat 301 causes different actuators to press their corresponding contact dome against the corresponding switch pad, which a detector circuit (not shown) coupled to the switch pads interpretes as a “directional” pressure of the control.
FIG. 4 illustrates the conventional way of placing certain controls into a hand-held electronic device 401. At the time of writing this description the well-established practice is to place a display 402 in the middle of a generally elongated device 401, so that a human user naturally grabs the device with both hands and holds it in a horizontal position in front of him. The thumbs rest most conveniently against a top surface of the device, leaving the display 402 visible therebetween. It has been conventional to place a round, joystick-like control 403 onto the top surface beside the display 402, which is the natural location of one thumb. Similarly many prior art devices have a small number of individual, pressable keys 404 distributed onto the top surface, on the other side of the display 402, within easy reach of the user's other thumb.
FIG. 5 illustrates another known way of placing certain controls in a hand-held electronic device. The overall shape of the device 501 resembles two inter-linked handles or butt ends. In a normal operating position a human user grabs the device with both hands, places his thumbs against a top surface 502 to operate keys and/or joysticks (not shown) located thereon, and bends his index fingers to reach the trigger switches 503 located on a lower surface of the device 501.
The intuitiveness of the controls known from prior art in controlling the presentation of three-dimensional graphics is modest even at its best. Using joystick-like controls in portable electronic devices may become problematic if the joystick protrudes remarkably out of the overall appearance of the device. Another problem of prior art is that full three-dimensional control of displayed objects usually requires the user to manually select between available control modes.